The Tower is a Vertical Drop coaster I created with the loading station completely enclosed inside the tower. You drop down the first hill and explode out through a wall opening with sides you can see through to the outside as you drop.

The re-entry is a vertical up straight into the tower.

Download The Tower Track (http://www.lat-g.com/rct3/The%20Tower.trk)
Download The Tower Building (http://www.lat-g.com/rct3/The%20Tower.dat)

http://www.lat-g.com/rct3/The%20Tower.jpg

I re-built it as a test by putting the building down and adding the roller coaster afterwards and it worked great. I'd think you could do the coaster first and add the building after (might be easier).